Abstract
Publisher Summary This chapter discusses the mechanism of active transport at the level of the transport protein molecule. Ion translocation has to occur by movement of the ion binding site with bound ion attached, which is accomplished by means of a conformational change in the protein. The movement of the ion between fixed sites facing the two sides of the membrane cannot lead to active transport. Free energy transduction steps have to be thermodynamically coupled so that the total free energy change in each step is small. When the chemical potential of the bound ion changes, there has to be a compensating change in the same step, either in the chemical substrate or in the conformational free energy of the protein itself. This is a kinetic and not thermodynamic requirement. The first alternative (direct exchange) applies to the sarcoplasmic reticulum Ca2+ pump. The protein conformational transition itself contributes little to free energy bookkeeping.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
